Variations in blood pressure and heart rate in conscious rats with cervical lymphatic blockade.
The possible effects of cervical lymphatic blockade (CLB) on a series of parameters in conscious freely moving rats were analysed. Blood pressure (BP) and heart rate (HR) for conscious male Sprague-Dawley rats at 1, 3, 7, 11, 15 and 21 days after a CLB or a sham operation were monitored continuously for 24 hours with a computerized recording system. Since BP and HR were subjected to spontaneous variations, blood pressure variability (BPV) and heart rate variability (HRV) were expressed as the standard deviation of beat-to-beat BP and HR values. The baroreflex sensitivities (BRS) were determined by measuring the heart period (HP = 60,000/HR) prolongation in response to the elevation in BP induced by an intravenous administration of phenylephrine at 1, 7, 15 and 21 days after the CLB or sham operation. Compared with those in sham-operated rats, the values of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), HR and BRS in CLB rats were significantly lower, whereas the values of BPV and HRV were markedly raised in CLB rats at different time points. Furthermore, the impaired ultrastructure in the dorsomedial nucleus of the solitary tract (dmNTS) including degeneration, apoptosis and necrosis in neurons and gliacytes, were apparent from the 1st to 15th day but the changes were most significant at 7th day after CLB operation. Structural changes appeared to be closely related to functional changes of the dmNTS at each time point. Thus, in CLB conscious rats, a significant decline in blood pressure accompanied by dysfunction in its regulation might be due to the impaired structure in the dmNTS.
Zheng
Yan-Hong
YH
Department of Physiology, Shandong Univeristy School of Medicine, Jinan, People's Republic of China.
Xia
Zuo-Li
ZL
Chen
Lian-Bi
LB
Zhao
Xiao-Min
XM
Xia
Qing
Q
Song
Xi-Jun
XJ
D000818:Animals; D017209:Apoptosis; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D003243:Consciousness / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D042601:Lymphatic Vessels / Q000502:physiology* / Q000601:surgery*; D008297:Male; D009336:Necrosis; D009474:Neurons / Q000473:pathology / Q000648:ultrastructure; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017552:Solitary Nucleus / Q000473:pathology / Q000648:ultrastructure; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D014662:Vasoconstrictor Agents; D010656:Phenylephrine